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Ge Zhao, Jianrong Wang, Qingyun Tang, Dongming Lan, Yonghua Wang
MAS1 is a lipase isolated from Streptomyces sp. strain W007 with potential application in biotechnology. Structural analysis of MAS1 lipase showed that eight amino acids with bulkier side located in the substrate-binding pocket may be involved in affecting catalytic performance. Alanine substitutions of those residues were conducted to reduce steric clash of catalyzed pocket and probe their functional roles. The k cat /K m of mutants H108A, F153A, and V233A increased to 2.3-, 2.1-, and 1.4-fold, respectively...
February 15, 2018: Molecular Biotechnology
Fei Ge, Longbao Zhu, Anna Aang, Ping Song, Wanzhen Li, Yugui Tao, Guocheng Du
Yeast has been increasingly used as a host for the expression of enzymes. Compared to other expression systems, the yeast expression system has many advantages including its suitability for large-scale fermentation and its ability to modify enzymes. When expressed in yeast, many recombinant enzymes are N-glycosylated, and this may play an important role in their activity, thermostability and secretion. Although the mechanism underlying this process is not clear, the regulation of N-glycosylation by introducing or eliminating N-glycosylation at specific sites has developed into an important strategy for improving the production or catalytic properties of recombinant enzymes...
February 15, 2018: Biotechnology Letters
Rafeeque R Alyethodi, Umesh Singh, Sushil Kumar, Rani Alex, Rajib Deb, Gyanendra S Sengar, T V Raja, B Prakash
OBJECTIVES: In a recent publication, we reported the successful use of tetra primer-amplification refractory mutation system based polymerase chain reaction (T-ARMS-PCR) for genotyping of rs445709131-SNP responsible for the bovine leukocyte adhesion deficiency (BLAD) in cattle. The SNP is characterized by higher GC content of the surrounding region, hence, the previous protocol utilized dimethyl sulfoxide as PCR enhancer. Here, the reaction cocktail was modified with the use of thermostable strand displacement polymerase (SD polymerase) instead of commonly used Taq DNA Polymerase...
February 15, 2018: BMC Research Notes
Federica Rigoldi, Stefano Donini, Francesca Giacomina, Federico Sorana, Alberto Redaelli, Tiziano Bandiera, Emilio Parisini, Alfonso Gautieri
Amadoriases are a class of FAD-dependent enzymes that are found in fungi, yeast and bacteria and that are able to hydrolyze glycated amino acids, cleaving the sugar moiety from the amino acidic portion. So far, engineered Amadoriases have mostly found practical application in the measurement of the concentration of glycated albumin in blood samples. However, these engineered forms of Amadoriases show relatively low absolute activity and stability levels, which affect their conditions of use. Therefore, enzyme stabilization is desirable prior to function-altering molecular engineering...
February 14, 2018: Scientific Reports
Jianfei Ding, Tianlin Ma, Cuixia Yan, Rong Shao, Wei Xu, Zhi Yun
The H6P2W18O62/MCM-41-SUP was first synthesized using supercritical impregnation as highly efficient catalyst during glycerol conversion reaction. For comparison, the H6P2W18O62/MCM-41 prepared by conventional wet impregnation was also studied. The catalysts were studied using XRD, BET, FTIR, SEM, TEM, pyridine-FTIR, NH3-TPD, TG, ICP and elemental analysis. The characterization results showed that the preparation condition of supercritical carbon dioxide contributed to improve the dispersion of H6P2W18O62 on MCM-41, strengthen the interaction between H6P2W18O62 and MCM-41, increase the thermostability of H6P2W18O62 and enhance the amount of medium and Brønsted acid sites on the catalyst...
April 1, 2018: Journal of Nanoscience and Nanotechnology
Xiangyu Gu, Jiaxin Peng
Graphene oxide nanosheets was prepared, modification with 3-aminopropyltriethoxysilane and used as the carrier for immobilization of NADH oxidase (NOX) from Streptococcus mutans. The prepared nanosheets were characterized with FTIR. A high immobilization yield of 92% and activity recovery of 91% were achieved at pH 7.0 and 25 °C. The thermostability of the immobilized NOX was improved about 60% compared with the free enzyme. And the immobilized NOX preserved about 92% of its initial activity after 500 h storage at 4 °C, while free NOX was totally denatured after 200 h at the same conditions...
June 1, 2018: Journal of Nanoscience and Nanotechnology
Noora Barzkar, Ahmad Homaei, Roohullah Hemmati, Seema Patel
Thermostable proteases are important in biotechnological and industrial sectors, due to their stability against denaturing agents and chemicals. The feature that gives them such unique applicability is their reaction at high temperatures, which affords a high concentration of substrate, and less risk of microbial contamination. Nearly 65% of industrial proteases are isolated from marine microbial source, and they can significantly resist a wide range of organic solvents at high temperatures. The most important trait of marine organisms is their adaptability, which allows them to grow optimally in harsh environments such as high salt, temperatures, and pressure-the characteristics of deep-sea hot springs and geothermal sediments...
February 13, 2018: Extremophiles: Life Under Extreme Conditions
Xiutao Chen, Weiguang Li, Peng Ji, Yang Zhao, Chengyao Hua, Chao Han
Endoglucanases are increasingly applied in agricultural and industrial applications as a key biocatalyst for cellulose biodegradation. However, the low performance in extreme conditions seriously challenges the enzyme's commercial utilization. To obtain endoglucanases with substantially improved activity and thermostability, structure-based rational design was carried out based on the Chaetomium thermophilum β-1,4-endoglucanase CTendo45. In this study, five mutant enzymes were constructed by substitution of conserved and noncatalytic residues using site-directed mutagenesis...
February 13, 2018: Scientific Reports
Emel Timucin, Osman Ugur Sezerman
Magnesium deficiency increases susceptibility of plants towards heat stress. The correlation between magnesium levels and stress response has been studied at the physiological level, albeit the molecular explanation to this relationship remains elusive. Among diverse pathways implicated in the heat stress, the abscisic acid (ABA) signal modulates the heat stress response by magnesium dependent phosphatases (PP2Cs). Exclusively, sequestration of PP2Cs by ABA receptors (PYLs) in the heterodimer form activates the stress response through ABA responsive transcription factors...
February 13, 2018: Journal of Chemical Information and Modeling
Zheng Xie, Yongzhong Wu, Xingming Sun, Shixin Liu, Fukun Ma, Gang Zhao, Xiaopeng Hao, Shuyun Zhou
Hydrophilic hydroxylated hexagonal boron nitride nanosheets (BNNSs), also called 'white graphene', exhibit high water solubility, compatibility, dispersity with physical and/or chemical effects on the gel matrix, and unexpected but outstanding near-infrared adsorption and nonlinear optical limiting properties. These properties mean that hydroxylated BNNSs are suitable for practical applications in solidification and devices. Hydroxylated BNNSs are doped into an organically modified silicate matrix through a facile sol-gel process...
February 13, 2018: Nanoscale
Roman Brunecky, Daehwan Chung, Nicholas S Sarai, Neal Hengge, Jordan F Russell, Jenna Young, Ashutosh Mittal, Patthra Pason, Todd Vander Wall, William Michener, Todd Shollenberger, Janet Westpheling, Michael E Himmel, Yannick J Bomble
Background: Thermophilic microorganisms and their enzymes offer several advantages for industrial application over their mesophilic counterparts. For example, a hyperthermophilic anaerobe, Caldicellulosiruptor bescii, was recently isolated from hot springs in Kamchatka, Siberia, and shown to have very high cellulolytic activity. Additionally, it is one of a few microorganisms being considered as viable candidates for consolidated bioprocessing applications. Moreover, C. bescii is capable of deconstructing plant biomass without enzymatic or chemical pretreatment...
2018: Biotechnology for Biofuels
Gulam Rabbani, Eun Ju Lee, Khurshid Ahmad, Mohammad Hassan Baig, Inho Choi
Tolperisone hydrochloride (TH) has muscle relaxant activity, and has been widely used for several years in clinical practice to treat pathologically high skeletal muscle tone (spasticity) and related pains. The current study was designed to explore the binding efficacy of TH with human serum albumin (HSA) using a multispectroscopic approach, FRET, esterase-like activity, and a molecular docking method. A reduction in fluorescence emission at 340 nm of HSA was attributed to florescence quenching by TH via a static quenching type...
February 12, 2018: Molecular Pharmaceutics
Douglas S Parsons, Christer Hogstrand, Wolfgang Maret
A significant aspect of the control of cellular zinc in eukarya is its subcellular re-distribution. One of the four human vesicular zinc transporters, ZnT8, supplies the millimolar zinc concentrations of insulin granules in pancreatic β-cells, affecting insulin processing, crystallisation, and secretion. ZnT8 has a transmembrane and a C-terminal cytosolic domain; the latter has important functions and purportedly mediates protein-protein interactions, senses cytosolic zinc, and/or channels zinc to the transport site in the transmembrane domain...
February 11, 2018: FEBS Journal
Binchun Li, Yaru Ji, Yanqin Li, Guobin Ding
A putative glycoside hydrolase family 78 α-l-rhamnosidase BtRha78A from Bacteroides thetaiotaomicron VPI-5482 was heterologously over-expressed in Escherichia coli. Enzymatic properties of recombinant BtRha78A were characterized in detail. Recombinant BtRha78A might efficiently hydrolyze p-nitrophenyl α-l-rhamnopyranoside. BtRha78A displayed the highest activity at 60 °C in pH 6.5. BtRha78A exhibited a good pH stability and relatively high thermostability. BtRha78A could be tolerant of a low concentration of alcohols...
February 2018: 3 Biotech
Vishakha A Pawar, Anil S Prajapati, Rekha C Akhani, Darshan H Patel, R B Subramanian
A thermostable keratinase designated as KBALT was purified from Bacillus altitudinis RBDV1 from a poultry farm in Gujarat, India. The molecular weight of the native KBALT (nKBALT) purified using ammonium sulfate and ion exchange and gel permeation chromatography with a 40% yield and 80-fold purification was estimated to be ~ 43 kDa. The gene for KBALT was successfully cloned, sequenced and expressed in Escherichia coli. Recombinant KBALT (rKBALT) when purified using a single step Ni-NTA His affinity chromatography achieved a yield of 38...
February 2018: 3 Biotech
Yeong-Jun Park, Byung Kwon Jung, Sung-Jun Hong, Gun-Seok Park, Jerald Conrad Ibal, HuyQuang Pham, Jae-Ho Shin
The enzyme xylose isomerase (EC, XI) is responsible for theconversion of an aldose to ketose, especially xylose to xylulose. Owing to the ability of XI to isomerize glucose to fructose, this enzyme is used in the food industry to prepare high-fructose corn syrup. Therefore, we studiedthe characteristics of XI from Anoxybacillus kamchatkensis G10, a thermophilic bacterium. First, a gene coding for XI (xylA) was insertedinto the pET-21a (+) expression vector and the construct was transformed into an Escherichia coli competent cell BL21 (DE3)...
February 13, 2018: Journal of Microbiology and Biotechnology
Dominik Danso, Christel Schmeisser, Jennifer Chow, Wolfgang Zimmermann, Ren Wei, Christian Leggewie, Xiangzhen Li, Terry Hazen, Wolfgang R Streit
Polyethylene terephthalate (PET) is one of the most important synthetic polymers used nowadays. Unfortunately, the polymers accumulate in nature and until now, no highly active enzymes are known that can degrade it at high velocity. Enzymes involved in PET degradation are mainly α/β-hydrolases like cutinases and related enzymes (E.C. 3.1.-). Currently, only a small number of such enzymes are well characterized. Within this work, a search algorithm was developed that identified 504 possible PET hydrolase candidate genes from various databases...
February 2, 2018: Applied and Environmental Microbiology
Dawei Ni, Wei Xu, Yuxiang Bai, Wenli Zhang, Tao Zhang, Wanmeng Mu
Levan, a versatile fructan, possesses promising prospects for application in the food and pharmaceutical industries and in many other fields due to the superior physicochemical properties and physiological functions of this fructan. In this study, a thermostable levansucrase was identified from Lactobacillus reuteri LTH5448. This enzyme shared higher identity with reported inulosucrases than levansucrases but, unexpectedly, yielded a levan-type fructan. Structural analysis of the produced polysaccharide revealed that the glycosidic bonds were β-(2, 6) linkages, and the average molecular weight was 3...
February 6, 2018: International Journal of Biological Macromolecules
Rajesh Kumar Sahoo, Mohit Kumar, Swati Mohanty, Matthew Sawyer, Pattanathu K S M Rahman, Lala Behari Sukla, Enketeswara Subudhi
The production of biofuel using thermostable bacterial lipase from hot spring bacteria out of low cost agricultural residue olive oil cake is reported in the present paper. Using a lipase enzyme from Bacillus licheniformis, a 66.5% yield of methyl esters were obtained. Optimum parameters were determined, with maximum production of lipase at a pH of 8.2, temperature 50.8°C, moisture content of 55.7% and bio-surfactant content of 1.693 mg. The contour plots and 3D surface responses depict the significant interaction of pH and moisture content with bio-surfactant during lipase production...
February 9, 2018: Preparative Biochemistry & Biotechnology
Lei Chen, Sheng Chen, Jing Wu, Dan Wu
We used in vitro molecular evolution technology by error-prone PCR and high-throughput screening to improve thermostability of Bacillus flexus CCTCC 2015368 β-amylase. Mutant D476N with significant thermostability increase was selected by LB agar starch plate colorimetric assay and 96-well plate enzyme activity assay. The optimum pH was 6.5 for the mutant D476N, compared to 7.0 of the wild type. The optimal temperature was 55 ℃ for both mutant D476N and the wild type. The T₅₀ value of the mutant D476N was 4 ℃ higher than that of the wild type...
February 25, 2018: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
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